CVE-2025-50398Public exploitNetwork attack vector

Router crash via unchecked fac_password buffer copy

Published Dec 16, 2025 · Updated Dec 16, 2025

Buffer overflow in Mercury D196G firmware d196gv1-cn-up_2020-01-09_11.21.44 allows remote attackers to crash the router via HTTP. The sub_404CAEDC function processes the fac_password value from a webPwd JSON request without checking its length, so an oversized string overflows its destination buffer. The published proof of concept includes a session cookie and stok token, while CISA assesses no privileges as required; the demonstrated consequence is a device crash.

CVSS severity9.8
Critical
EPSS probability0.42%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Buffer overflow in Mercury D196G firmware d196gv1-cn-up_2020-01-09_11.21.44 allows remote attackers to crash the router via HTTP. The sub_404CAEDC function processes the fac_password value from a webPwd JSON request without checking its length, so an oversized string overflows its destination buffer. The published proof of concept includes a session cookie and stok token, while CISA assesses no privileges as required; the demonstrated consequence is a device crash.

The record

CVE
CVE-2025-50398
Published
Dec 16, 2025
Updated
Dec 16, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-120, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 16, 2025CVE publishedPublication date reported by the CVE source.
  2. Dec 16, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.8CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
T1499.004Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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